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Jam-27, 1931. A. M. MASTERS BLACKBOARD FRAME MOUN'HNG,

Filed April 23. 1928 2 Sheets-Sheet l Azerzlzzmszem 44 43 wxmx 3 7 Jan.27, 1931. A. M. MASTERS 1,790,549 7 BLACKBOARD FRAME MOUNTING FiledApril 23,1928 2 Sheets-Sheet 2 Patented Jan. 27, 1931 UNITED STATESPATENT OFFICE ALBERT M. MASTERS, OF FRANKFORD, PHILADELPHIA,PENNSYLVANIA, ASSIGNO R TO MASTERS STEEL FRAME COMPANY, OF PHILADELPHIA,PENNSYLVANIA, A 00R:

PORATION OF DELAWARE BLACKBOARD-FRAME MOUNTING Application filed April23, 1928. Serial No. 222,230.

I The present invention relates to an improved blackboard framemounting, the purpose of which is to provide a device of this kind,constructed to removably clamp and support the blackboard in position.

In order to accomplish this, it is the purpose to provide upper andlower sheet metal channel members for the reception of the board, clampsfulcrumed on adjusting screws to force the board toward the outerflanges of the channels and clamp the same in position, therebeingsuitable felt pads on opposite sides of the board where it is clamped,to prevent breaking of the board.

Another feature of the invention consists of longitudinal depressions inthe back walls of the channels to steady and insure positioning theadjusting screws, in combination with aflange or other support forming apart ofthe lower channel, to support the board.

A further feature of the invention consists in forming the lower channelwith a chalk and eraser trough, said trough forming a part of the lowerchannel.

It is to be understood that the particulars herein given are in no waylimitative, and that while still keeping within the scope of theinvention, any desired modification of details and proportions may bemade in the construction of the appliance according to circumstances.

The invention comprises further features and combination of parts to behereinafter set forth, shown in the drawings and claimed.

In the drawings:

Figure 1is a view in front elevation of a blackboard frame mountingconstructed in accordance of the invention.

Figure 2is a sectional view on line 2-2 of Figure 1, showing theblackboard in position, and the clamping means tightened.

Figure 3is a detailed view in perspective of one of the upper clamps inthe upper channel.

Figure 4is a sectional view similar to Figure 2, but showing the clampsloosened. Figure 5is a detailed perspective View of the upper channel.

Figure 6is a detailed perspective View of the lower channel.

Referring to the drawings, 1 identifies parts of the wall constructionof a room and 2 and 3 are upper and lower channels for the support of ablackboard 4:.

The upper channel is constructed of sheet metal and has a fibre filler5, suitable screws 6 passing through the channel and through the fillerto hold the channel in place, the screw entering the upper part of thewall 1.

The outer thickness of the channel has a longitudinal shoulder 7 Theshoulder 7, though it may not support the part 18 of the jaw member 10of the upper clamp, it does act asan abutment for the part 18 during itssliding action on the outer wall or thickness of the channel, providedthe clamp member is tightened sufficiently to draw the clamp membertoward the outer wall of the channel.

Furthermore the shoulder or bend 7 of the" outer wall of the channelpermits the outer wall to yield more readily than it would if theshoulder or bend 7 did not exist. The reason for providing yieldability,is to permit the, blackboard to give uniformly throughout its area. Forexample if the blackboard 4 should be held rigid at its marginal edgeswith nothing behind the center of the board, the board would tend toyield in the center and if the pressure should be sufficient the boardwould crack, hence by yield' ably supporting the marginal edges of theboard, the board may yield substantially and with uniformity throughoutits entire area, and such yieldability is considerably assisted by thepaddings 11 and 12.

The inner thickness of the channel 2 has ing in contact with the boardwhich ispreferably made of slate or any other sultable material, hencepreventing the blackboard from cracking and to insure holdlng the blackboard firm, it being obvious that the outer wall of the channel at apoint below the filler more or less gives as pressure is applied to theblackboard when writing and especially when erasing or otherwisecleanlng the blackboard. The outer thickness of the channel has aninternal flange 13 so as to more or less space the blackboard inwardly.

The lower channel 3 is somewhat similar to the upper channel, but withvariations such as forming the outer thickness of the channel with achalk or eraser receiving trough 14. The outer thickness of the channel3 also has a longitudinal shoulder 15, as well as the inner thickness ofthe channel 3 having a longitudinal groove 16 which and the shoulder 15perform the same function as the corresponding parts on the channel 2.Furthermore the outer thickness of the channel 3 has its inturned flange13a provided with a laterally inward turned flange 17 on which the loweredge of the blackboard 4 rests.

With these exceptions, as previously stated the lower channel 3 and itsattendant parts as well as the clamps substantially correspond withsimilar features of the channel 2, therefore the same referencecharacters p y- The clamps 10 in each instance are substantiallyangular, and their shorter ends 18 have a moving fulcrum or hearing onthe outer thickness of the channels, enabling the screws 9 whentightened to cause the clamps to rock ner as to prevent the nuts andthereby draw the clamps tight against the blackboard.

The screws 9 above and below carry nuts 9a, and theedges of these nutscooperate with shoulders 10a on the clamfs 10 in such manrom turning,when the screws 9 are tightened or loosened, so as 'to draw the clampsand their felt pieces 11 toward the black card. The felt pieces 11 areadhesively fastened to the clamps, while the felt strips ,12 areadhesively fastened to the flanges 13 and 13a and extend longitudinallythereof. The flanges 13;and 13a have reasonable resiliency, so as toprovide for a yieldable 7 joint between the flanges andthe blackboardand the blackboard and the clamps. It is a well established fact, andhas been for years, that slate blackboard sections or slabs when splitfrom the large blocks mined at thequarry are of varying thickness;.thatis, thicker at one end or one side than at th other end or other side,or possibly thicker in the middle; It hasalso'been customary inconstructing slate blackboard slabs to surface only one face, in whichcase the slate blackboard slabs still remain thicker at one end or oneside than at an opposite end or opposite side. In view of this, therehas been difficulty in mounting the slate blackboard slabs,

so as to arrange the slabs in order that their surfaced faces are allflush, particularly at the joints between the slabs, necessltatmg wedgesand the like to force the slabs 1nto position so that their finishedfaces are all flush.

In view of these facts, one of the essential purposes of the presentinvention is to proadjustment from the front of the blackboard,

whereas in the mounting oflother slabs, such as glass slabs in storeshow windows and thelike, the clamps can be adjusted and applied inposition from the interior, as well as from the exterior, preferablyfrom the interior. The record of this application will show that it hasbeen a customary practice to use slate blackboard slabs of varyingthicknesses, evidence of this fact having been made of record in theapplication.

The invention having been set forth, what a is claimed is:

1. In a blackboard frame mounting, the combination with upper and lowerchannels provided with means for fastening the channels to a stationarysupport, said channels having inner and outer yieldable walls, the"outer wall constituting a jaw member of a clamp, of anelement'constituting a second jaw member of said clamp and having asliding fulcrum on the first jaw member, said clamp adapted to support ablackboard inter-' lnosed between the two 'jaw members, said rst jawmember engaging the blackboard immediately just past the edge of theblackboardto hold the latter,

' and means passing throughthe first jaw member and operativelyconnecting with the'interme'diate jaw member for tightening theintermediate member against-the blackboard, said intermediate jaw memberreaching materially farther toward I the center of the blackboard thanthe outer jaw member, themarginal edges .of the outer ,walls merelyektending pa's'tithe v edge of the blackboard-far enough toihelditheboard but -not far enough to limit'the amount of writ- 2; In ablackboard frame mounting, the

ing surface 0 the board.

combination with ,upper and lower channels Y provided with means forfastening the chain nels to a statlonary support, said channels; H

having inner and outer walls, each outer wall constituting a jaw memberof a clamp, of an element constituting a second jaw member of said clampand being operatively mounted intermediate the inner and outer walls,said clamp adapted to support a blackboard inter.-

posed and clamped between the outer wall and said element, the outerwalls engaging the blackboard immediately just past the edges of theblackboard to hold the latter, means passing through the outer Walls andoperatively connected with the intermediate elements for tightening saidjaw members against the blackboard, the outer wall of the lower channelterminating in a lateral flange acting asa support with which theblackboard engages to support the board and prevent downward .movement.

3. In a blackboard frame mounting, the combination with upper and lowerchannels provided with means for fastening the channels to a stationarysupport, said channels having inner and outer walls, each outer wallconstituting a jaw member of a clamp, of an element constituting asecond aw member of said clamp and being operatively mountedintermediate the inner and outer walls, said clamp adapted to support ablackboard interposed and clamped between the outer wall and saidelement, the outer walls engaging the blackboard immediately just pastthe edges of the blackboard to hold the latter, means passing throughthe outer walls and operatively connected with the intermediateelementsfor tightening said jaw members against the blackboard, said secondintermediate jaw members engaging with the blackboard and reachingmaterially farther 'toward the center of the blackboard than the outerwalls, the marginal edges of the outer walls merely extending past themarginal edge of the blackboard far enough to hold the board but not farenough to limit the amount of writing surface of the board.

"4. In a blackboard frame'mounting, the combination with upper and lowerchannels provided with means for fastening the channels to a stationarysupport, said channels having inner and outer walls, each outer wallconstituting a jaw member of a clamp, of an element constituting asecond jaw member of said clamp and being operatively mountedintermediate the inner and outer walls, said clamp adapted to support ablackboard interposed and clamped between the outer wall and saidelement, the outer walls engaging the blackboard immediately ust pastthe edges of the blackboard to hold the latter,

means passing through the outer walls and 'operatively connected withthe intermediate elements for tightening said aw members against theblackboard, the outer wall of the lower channel terminating in a lateralflange acting as a support with'which the blackboard engages to supportthe board and prevent downward movement, said second intermediate jawmembers engaging with the blackboard and reaching materially'farthertoward the center of the blackboard than the outer walls, the marginaledges of the outer walls merely extending past the marginal edge of theblackboard far enough toliold the board but not far enough to limit theamount of writing surface of the board.

5. In a blackboard frame mounting, the combination with upper and lowerchannels .provided with means for fastening the same to a stationarysupport, said channels having inner and outer walls, each outer wallconstituting a jaw member of a clamp, of an element constituting asecond jaw member of said clamp and being located intermediate the innerand outer walls, both of said elements having sliding fulcrums on theouter walls,'s-aid clamp adapted to support a blackboard interposed andclamped between both sets of jaw members, screws passing through theouter walls and operatively connecting with the second jaw members fortightening them against the blackboard, and abutment means carried bythe outer walls and cooperating with the intermediate-elements forlimiting the sliding fulcrums of said second jaw members.

6. In a blackboard frame mounting, the combination with upper and lowerchannels provided with means for fastening the same to a stationarysupport, said channels having inner and outer walls, each outer wallconstituting a jaw member of aclamp, of an element constituting a secondjaw member of said clamp and being located intermediate the inner andouter walls, both of said elements having sliding fulcrums on the outerwalls, said clamp adapted to support a blackboard interposed and clampedbetween both sets of jaw members, screws passing through the outer wallsand operatively connecting with the second jaw members for tighteningthem against the blackboard, and abutment means carried by the outerwalls and cooperating with the intermediate elements for limiting thesliding fulcrums of said second jaw members, the outer wall of the lowerchannel terminating in a lateral flange acting as a support with whichthe blackboard engages, to support the board and prevent downwardmovement thereof.

7. In a blackboard frame mounting, the combination with upper and lowerchannels provided with means for fastening the same sets of jaw members,screws passing through ,the outer walls and operatively connecting withthe second jaw members for tightening them against the blackboard, andabutment means carried by the outer walls and-'cooperating with theintermediate elements for l imiting the sliding fulcrums of said secondjjaw members, both intermediate jaw memers engaging with the blackboardand reaching materially farther toward the center of the blackboard thanthe outer walls, the marginal edges of the outer walls merely extend ingpast the marginal edges of the board far enough to hold the board butnot far enough to limit the amount of writing surface of the board. I

8. In a blackboard frame mounting, the combination with upper and lowerchannels provided with means for fastening the same to a stationarysupport, said channels having inner and outer walls, each outer wallconstituting a jaw member of a clamp, of an element constituting asecond jaw member of said clamp and being located intermediate theinner'and outer walls, both of said elements having sliding fulcrums onthe outer walls, said clamp adapted to support a blackboard interposedand clamped between both sets of jaw members, screws assing through theouter walls and operatively connecting with the second jaw members fortightening them against the blackboard, and abutment means carried bythe outer wallsand cooperating with the intermediate elements forlimiting the sliding fulcrums of said second aw members, bothintermediate jaw memers engaging with the blackboard and reachmgmaterially farther toward the center of the blackboard than the outerwalls, the marginal edges of the outer walls merely extending past themarginal edges of the board far enough to hold the board but not farenough to limit the amount of writing surface of the board, the outerwall of the lower channel being outwardly bent on itself, therebycausing a chalk and eraser trough to be formed thereon.

9. In a blackboard frame mounting, upper and lower channels havingfillers and provided with means for securing the channels to astationary support, said channels having inner and, outer yieldablewalls extending beyond the fillers, eachof the outer walls constitutingajaw member of a clamp, an element operatively supported intermediatethe inner and outer walis of both channels and associated with an outerwall and thereby constituting a second'jaw member of said clamp, both ofsaid second jaw members operatively. connecting with the inner and outerwalls, thereby permitting the inner and outer walls of both channels toyield,

said clamp adapted to support a blackboard interposed betweenthe outerwalls and the second jaw members, and devices passing through the outerwalls and through the second jaw members, with means on said devices andcooperating with the second jaw members to tighten'them into position.

10. In a blackboard frame mounting, upper and, lower channels havingfillers and pro- Vided with means for securing the channels to astationary support, said channels having inner and outer yieldable wallsextending beyond the fillers, each of the outer walls constituting a jawmember of a clamp, an element operatively supported intermediate theinner and outer Walls of both channels and associated with an outer walland thereby constituting a second jaw member of said clamp, both of saidsecond jaw members operatively connecting with the inner and outerwalls, thereby permitting the inner and outer nels to a stationarysupport, said channels having inner and outer yieldable walls extendingbeyond the fillers, each of the outer walls constituting a jaw member ofa clamp, an element operatively supported intermediate the inner andouter walls of both channels and associated with an outer wall andthereby constituting a second jaw member of said clamp, both of saidsecond aw members operatively connecting with the inner and outer walls,thereby permitting the 1nner and outer walls of both channels to yield,said clamp adapted to support a blackboard interposed between the outerwalls and the second jaw members, and screws passing through the outerwalls and through the second jaw members, nuts on said screws andcooperating with the second jaw members to tighten them in position,said second aw members having means cooperating with the nuts topreventv movement, thereof.-

12. In a blackboard frame mounting, upper and lower channels havingfillers and provided with means for securing the channels to astationary support, said channels having inner and outer yieldable wallsextending beyond the fillers, each of the outer walls constituting a jawmember of a clamp, an element operatively supported intermedlate theinner and outer walls of both channels and associated with an outer walland thereby constituting a second jaw member I of said clamp, both ofsaid second jaw members operatively connecting with the inner and outerwalls, thereby permitting the inner and outer walls of both channels toyield,

cooperating with the second jaw members to tighten them in position,said second jaw members having means cooperating with the nuts toprevent movement thereof, the inner walls of both channels having meanswith which the screws engage to hold the screws straight when adjusted.

13. In a blackboard frame mounting, the combination with upper and lowerchannels provided with means for fastening the channels to a stationarysupport, said channels having inner and outer walls, each outer wallconstituting a jaw member of a clamp, of an element constituting asecond jaw member of said clamp and being operatively mountedintermediate the inner and outer walls, said clamp adapted to support ablackboard interposed and clamped between the outer wall and saidelement, the outer walls engaging the blackboard immediatelyjust pastthe edges of the blackboard to hold the latter, means passing throughthe outer walls and operatively connected with the intermediate elementsfor tightening. said aw members against the blackboard, the outer wallof the lower channel terminating in a lateral flange acting as a supportwith which the blackboard engages to support the board and preventdownward movement, the outer walls of both channels and the second jawmembers having their adjacent faces padded for engagement with saidblackboard.

14;. In a blackboard frame mounting, upper and lower-channels providedwith means for securing the channels to a stationary support, saidchannels having inner and outer yieldable walls, each of said outerwallsconstituting a jaw member of a clamp, an element locatedintermediate the inner and outer walls and operatively associated witheach of the outer walls, and constituting a second jaw member of saidclamp, said clamp adapted to support a blackboard interposed between theouter walls and the second jaw members, the outer walls and said secondjaw members having their adj acent'faces provided with cushions forengagement with the blackboard, means operatively connecting the outerwalls and said second jaw members to clamp the board in position, said'connecting means operatively engaging with the 1nner walls for yieldablysupporting the blackboard.

15. In a blackboard frame mounting, upper and lower channels providedwith means for securing the channels to a stationary support,saidchannelshaving inner, and outer yieldable walls, each of said outerwalls con stituting a jaw member of a clamp, an element locatedintermediate the inner and outer walls and operatively associated witheach of the outer walls, and constituting a second jaw member of saidclamp, said clamp adapted to support a blackboard interposed between theouter walls and the second jaw members, the outer Walls and said secondjaw members having their adjacent faces provided with cushions forengagement with the blackboard, means operatively connecting the outerwalls and said second jaw members to clamp the board in position, saidconnecting means operatively engaging with the inner Walls for yieldablysupporting the blackboard, both of said second jaw members reachingmaterially farther toward the center of the blackboard than the outerwalls, the marginal edges ofthe outer walls merely extending past themarginal edge of the blackboard far enough to hold the board but not farenough to limit'the amount of writ ing surface of the board.

16. In a blackboard frame mounting, upper and lower channels providedwith means for securing the channels to a stationary support, saidchannels having inner and outer yieldable walls, each ofsaid outer wallsconstituting a jaw member of a clamp, an element located intermediatethe inner and outer walls and operatively associated with each of theouter walls, and constituting a second jaw member of said clamp, saidclamp adapted to support a blackboard interposed between the outer wallsand the second jaw members, the outer walls and said second jaw membershaving their adjacent faces provided with cushions for engagement withthe blackboard, means operatively connecting the outer walls and saidsecond jaw members to clamp the board in position, said connecting meansoperatively engaging with the inner walls for yieldably supporting theblack board, the outer wall of the lower channel having a lateral flangewith which the blackboard engages to support and prevent downwardmovement of same.

17. In a blackboard frame mounting, upper and lower channels providedwith means for securing the channels to a stationary sup port, saidchannels havin inner and outer yieldable walls, each of sa d outer wallsconstituting a jaw member of a clamp, an element located intermediatethe inner and outer walls and operatively associated with each of theouter walls, and constituting a second jaw member of said clamp, saidclamp adapted to support a blackboard inter osed between the outer wallsand the secon jaw members, the outer walls and said second jaw membershavin their adjacent -faces'pro-' vided with cushionsfor engagementwith'the blackboard, means operatively connecting the outer 'walls andsaid second jaw members to alamp the board in position, said connectingmeans operatively engaging with the inner walls for yieldably supportingthe blackboard, the outer wall of the lower channel having a lateralflange with which the blackboard engages to support and prevent downwardmovement of same, both of said second jaw members reaching materiallyfarhold the board but not far enough to limit the amount of writingsurface of the board.

Ext

'18. In a blackboard frame mounting, an outer continuous marginalclamping element, a plurality of slate blackboard sections to bearranged adjacent to and back of said elerality of individual clampingelements arranged at infrequent intervals and adapted to engage with theinner rear uneven faces of the slate blackboard sections, therebykeeping the outer faces of the sections Hush and even throughout theirentire area and at the joints, and means operable from the front of theblackboard for connecting the individual clamping elements to thecontinuous marginal clamping element.

I 19. A blackboard frame mounting, comprising an outer continuousmarginal frame constituting one element of a clamp, said clamp adaptedtoisupport a plurality of slate blackboard sections adjacent and to therear and engaged with said element, a plurality of individual clampingjaw elements adjacent to and cooperative with the rear' tions flushagainst the first element, and

use

means connecting the individual clampingjaw elements with the firstelement, said connecting means being operable from the front of theblackboard to tighten the individual clamping jaw elements against theinner uneven faces of the blackboard sections.

20. A blackboard frame mounting, comprising an outercontinuous ma rginalframe constituting one element of a clamp, said clam adapted to supporta plurality of slate black board sections adjacent and to the rear andengaged with said element, a plurality of individual clamping jawelements adjacent to and cooperative with the rear uneven faces of theblackboard sections, said individual clamping jaw elements havingsliding fulcrums-on and cooperative with the first I element andengaging the rear uneven faces of the blackboard sections to retain'thesections with their outer finished surfaces flush,

21. A blackboard frame mountin compris-' ing an outer continuousmarginal rame constituting one element of a clamp, said clamp adapted tosupport a plurality of slate blackboard sections adjacent and to therear and engaged with said element, a plurality of individual clampingjaw elements adjacent to and cooperative with the rear uneven faces ofthe blackboard 7 sections, said individual clamping jaw elements havingsliding fulcrums on and cooperative with the first element and engagingthe rear uneven faces of the blackboard sections to retain the sectionswith their outer finished surfaces flush, and means connecting theindividual jaw elements to the first element, said means beingadjustable to increase and decrease the pressure of the individual jawelements against the blackboard sections, and abutment means carried bythe first clamping element and cooperating with the individual jawelements for limiting the sliding fulcrums of the individual jawelements.

22. A blackboard frame mounting, comprising a frame of channelconstruction, having inner and outer walls, said outer wall constitutinga jaw member of a clamp, a plurality of individual elements constitutingopposing jaw members of said clamp and being located between the wallsof the channel, said first jaw elements being marginally continuprisinga frame of channel construction hav-- ing inner and outer walls, saidouter wall constituting a jaw member of a clamp, a plurality ofindividual elements constituting opposing jaw members of said clamp andbeing located between the walls ofthe channel, said first jaw elementbeing marginally continuous, whereby the outer surfaced faces of slateblackboard sections, which are adapted to be supported by said clamp,may assume even and flush positions adjacent the joints between thesections, and means passing through the outer walls of the frame andcooperative vwith the inner walls and connected operatively with theindividual clamping elements for adjusting them in position according tothe varying thicknesses of the blackboard sections,said individualclamping jaw elements having sliding fulcrums, and means cooperatingwith the individual clamping jaw elements for limiting the slidingfulcrums.

-24. A blackboard frame mounting, comprising an outer continuousmarginal frame constituting a continuous marginal jaw element of aclamp, the lower rail of said frame having means-to support a pluralityof slate blackboard sections adapted to be supported by said clamp andhaving their outer faces surfaced and their inner faces rough anduneven, a plurality of individual elements constituting Opposing jawelements of said clamp and located in the rear of and engaging with theunfinished faces of said sections, and means for each individual secondjaw member for clamping the same against the unfinished surfaces of saidsections according to the varying thicknesses of the slate blackboardsections, whereby the finished surfaces of the sections may be heldflush at their joints, and against the continuous marginal clamping jawelement. l

25. A blackboard frame mounting, comprising an outer continuous marginalframe -const1tutmg a continuous marginal jaw element ofa clamp, thelower rail of said frame having means to support a lurality of slateblackboard sections adapted to be supported by said clamp and havingtheir outer faces,

surfaced and their inner faces rough and uneven, a plurality ofindividual elements constituting opposing jaw elements of said clamp andlocated in the rear of and engaging with the unfinished faces of saidsectlons, and

means for each individual second jaw member for clamping the sameagainst the unfinished surfaces of said sections according to thevarying thicknesses of the slate blackboard sections, whereby thefinished surfaces of the sections may be held fl ush at their joints,and against the continuous marginal clamping jaw element, said meansbeing carried by the continuous marginal jaw member, the upper rail ofsaid frame extending far enough down below said means of the upper rail,wherebythe blackboard sections may be inserted upwardly into said clamp,so that their lower ends may subsequently engage with said supportingmeans.v

ture. 1

ALBERT M. MASTERS.

In testimony whereof he aflixes his signa-

